Automatic balancer.



M. LEBLANC.

AUTOMATIC BALANCER.

APPLICATION FILED MAR. 25. 1915.

Patented July 17; 1917.

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S E S N H To all whom a may mam nannies JLEJBBIIDMG, or name, a:

on, assiearon 'ro socm'rn anemia noun LEJXJPLOITMTIWII IDES PEOGEDES VIESTmG-HOUSlE-LEBLMC, 01E PARIS, FRANCE.

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Be it known that I, MAURICE Lnemno, a citizen of the Republic .of France, residing in Paris, France, have invented certain new and useful Improvements in Automatic Balancers, of which the following is a specification,

When it-is required that a rotor should rotate very rapidly, it is necessary that its geometric axis should coincide very approm'mately with one of its principal axes of inertia through its centerof gravity, which axis is called simply its axis of inertia in the following description.

If this condition is not fulfilled, if the rotor shaft is rigid and its bearings fixed, the rotor rotates around its axis of symmetry, but exerts strong reactions on its points of support. If the rotor shaft is flexible and rests in fixed hearings, or if the shaft is rigid and the bearings movable, or if a combination of these two conditions occurs, the rotor instead of rotating around its geometric am's, rotates around its axis of inertia, or at least around an axis very "near to the latter. In these conditlons there is no strong reaction on the points of support, but the shaft whirls accord ng to the ordinary expression, which consequently fatigues the parts attached to the rotating members. Also the rotor should generally rotate with a small amount of clearance within the stator; to avoid rubbing contacts, on account of the whirling action, it' is necessary to increase the clearance and thls is often disadvantageous.

The axis of inertia can be brought into coincidence with the .geometric axis by attaching at the ends of the shaft two masses, the positions of whose centers of gravlty are carefully arranged.

Two additional masses are sufficient, but if a rotor comprises several wheels, it is preferable to first adjust the center of gravity of every wheel, so that it coincldes with its geometric axis by means of an of the am's of inertia with the geometric AUTOMATIC n Specification of Illietteru Patent.

Patented duty it, an.

i mat application flied t'ulygtt, laimherial li o. 711,177. Divided jami this application flled'march 25,

. 1915. Seriaiito. 16,8611. 1(-

axis of the'whole rotor. In this way the stresses exerted on the shaft during the rotation are reduced to a. minimum It is very dificult in practice to insure scribed and claimed broadly balancers for a rotor shaft which is capable of rotation about a principal axis of inertia through its center of gravity, the balancers comprising masses secured to the rotor shaft and having one or more-circularv channels partlyfilled with mobile material by means of which the geometric axis of the rotor and said am's of inertia are automatically brought into at least approximate coincldence. The present application is a division' of the aforesaid application and is based upon .the use of mobile material which, having once taken a counter-balancing form during rotation, is solidified or stifil'ened into such form permanently; such material, for example, may be tin, or similar metal, which is melted by heat during its first rotation, and which is thereafter cooled so as to solidify it; or-cement which is quite plastic ormobile when first used,

and which hardens quickly and permanently Fig. 2 is a side elevation of another,

style, showing the channels carrying the balancing material in section..

Fig. 3 is a cross section of a meansfor su porting the rotor.

ach balancer consists of a ring of the balancing material concentric with the geometric axis wy of the rotor.

In Fig. 1 the rotor comprises several wheels R and each of these is provided on eachof its two opposite faces with circular channels a open toward the axis. In the construction of Fig. 2 the rotor comprises a drum B on the ends of which are mounted similar grooved rings a, two concentric grooves on each end of the drum. The bal ancing mass indicated at b partly fills the circular channels referred to. or some fusible alloyis to -be used, it I is melted just before starting, after the halancers have been mounted on movable bearings which will permit them to rotate about their principal axis of inertia. As the balancer rotates the metal or alloy will be dislaced in the channel under the influence of the forces of inertia. and will assume a balancing position or shape, in which shape it will be solidified by cooling durin the continued rotation. After it has ha time to cool the rotor is sto pod and will be balanced once for all. I the counter-balancing material be placed in closed grooves, as m my previous application; above-referred-to, no special precaution is necessary to prevent the escape of the tin when heated to liquefaction. With open grooves such as are illustrated in Figs. 1 and 2 the inside faces are thoroughly coated with tin prior to ro- .tation, but are .not heated, at least not to liquefaction, until the rotor has obtained speed, and the rotor is .not then stopped until the metal is again solidified.

Where there are several wheels B it is advisable to provide each of them with balancing masses and to mount them provisionally on a special shaft and balance them separately. Then when the wheels are as sembled on their proper shaft to constitute the rotor it is best to mount the rotor on special bearings permitting free displacement and to complete the balancing by heating the tin in the two end grooves to liquefaction while the rotation continues. Fig. 1 shows a single balancing mass on each of the faces of the wheels but it will be understood that they may be two or more concentric grooves on each face, as in Fig. 2. Instead of a fusible material such as the metals and alloys above-referred-to, any material may be used, such as a-pasty cement which will be mobile for a time, but will stiflen or set while the rotor is in motion andwill thus retain its balancing shape. In order that the balancers may accomplish the required results, that is, may bring into coincidence the axis of inertia and the geometric axis, it is necessary that the rotor should be able to select its axis of rotation at every instant as freely as possible; in i order that the rotation should always take place, if not about the axis of inertia of all the moving parts, at least about an axis approximating very closely to it. This condition is indispensable. -The rotors illustrated in the drawing should be mounted on a shaft which is free to select its axis of Where tin is shown at '1.

rotation during the process of generating the pro or shape for the balancmg masses and be ore it is put into actual use.

A transverse section of a suitable style of bearing for the rotor is shown in Fig. 3. The bearing rin fplpnthe shaft of the rotor r dthis is aring2 for limiting the lateral displacement of the bearing ring 1. A tube 3 penetrates the bearing 1 after passing through the limiting ring 2, which prevents these rings from turmng relatively to each other, but permits a suflicient play between them to allow a slight relative movement up and down, or to the right and left, or a slight reciprocation -in the axial direction.- Normally the limiting ring 2 is held fixed by three radial plates 4. When the strains on the ring 2 exceed a certain limit, the plates 4 bend and permit a slight movement. Oil is passed throu h the tube 3 under pressure. A portion of t e oil lubricates the shaft in the bearing ring 1. The remainder passes through orifices, such as 5, into the s ace between the two rings 1 and 2. In or er to damp the movements of the bearing ring 1, there are arranged between it and the inclosing ring 2 one or more ver thin concentric rings indicated in dotte lines at 6 and made of aluminum or celluloid or other suitable material.

What I claim is 1. The combination with a rotor shaft which is mounted in a pair of yieldin bearings in which it is adapted to be free y displaced so as to be capable of rotation about a principal axis of inertia through its center of gravity, of a balancer comprising a mass adapted to be first used in such condition that its particles are mobile and to assume a counter-balancing shape when in rotation, said mass bein solidified permanently into such shape, said rotating parts being of relatively large mass.

2. The combination with a rotor shaft which is mounted in a' pair of yielding bearings in which it is adapted to be freely displaced so as to be capable of rotation about a principal axis of inertia throu h its center of gravity, of a balancer COIIlPllS- mg a ring of easily fusible metal adapted to be first used in a fused condition so that its particles are mobile and assume a counter-balancing shape when in rotation, said metal being solidified permanently into such shape, said rotating parts being of relatively large mass.

3. The combination with a rotor shaft which is mounted in a pair of yieldin bearings in which it is adapted to be free y displaced s o as to be capable of rotation about a princlpal axis of inertia through its center of gravity, of a balancer comprising a balancing mass located in a circular channel in the rotor epening inward, said balancing In witness whereei, have hereunto si ed mass being of a substance Which is adapted my name in the presence of two subscri ing 1a to be first used in such condition that its Witnesses.

particles are mobile and assume a counter- 5 balancing shape when in rotation, said mass MAURICE LEBLANC' being permanently solidified into such shape, Witnesses: said rotating parts being of relatively large DE W. C. POOLE, J12,

mass. GABRIEL BELIJARD. 

